JP2006234413A - Method and device for inspecting image display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection method capable of accurately inspecting a liquid crystal light valve, based on the color of an inspecting image. <P>SOLUTION: The liquid crystal light valve 14G of an inspection object is arranged at a position Pg, and reference liquid crystal light valves 14R, 14B are arranged, respectively at positions Pr, Pb. The white inspecting image over the whole face is displayed on a screen 2, when no defect exists in the liquid crystal light valve 14G of the inspection object, and the inspecting image with a color is displayed on the screen 2, when a defect exists in the liquid crystal light valve 14G of the inspection object. The liquid crystal light valve 14G is thereby inspected accurately, based on the color of the inspecting image. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inspection method and an inspection apparatus for an image display device.

  Conventionally, a liquid crystal light valve capable of generating a colorless image pattern by controlling the transmitted light amount and the reflected light amount, and RGB (R is red, G is green, B is blue, A color liquid crystal panel that includes a color filter for applying a color such as a color filter or an interference filter such as a dichroic mirror and can display a monochromatic image such as RGB is known. In such color liquid crystal panel inspection, a single color liquid crystal panel is displayed with a single color inspection image, the inspection image is captured by a monochrome camera, and luminance distribution data in the inspection image is acquired. A method of inspecting a color liquid crystal panel based on luminance distribution data is common (see, for example, Patent Document 1).

  In the inspection method of Patent Document 1, since a monochrome camera is used as the image pickup means of the color liquid crystal panel, data related to the color of the inspection image displayed by the color liquid crystal panel is lost at the time of image pickup. However, since the inspection image displayed by the color liquid crystal panel is a single color and the color is uniform throughout, the data related to the color of the inspection image is also uniform throughout the color. The liquid crystal panel cannot be inspected. Therefore, in the inspection method of Patent Document 1, data related to the color of the inspection image is removed using a monochrome camera to obtain only the luminance distribution data in the inspection image, and a color liquid crystal panel is obtained based on the luminance distribution data. We are inspecting.

  In addition, instead of the monochrome camera in the inspection method of Patent Document 1, it is possible to use a color camera capable of acquiring data related to the color of the inspection target image together with the luminance distribution data in the inspection target image. Since the inspection image is a single color, even if data relating to the color of the inspection image is acquired by the color camera, this data is uniform throughout. For this reason, data relating to color cannot be used for the inspection of the color liquid crystal panel, and eventually the color liquid crystal panel is inspected based only on the luminance distribution data.

  In the inspection method disclosed in Patent Document 1, a color liquid crystal panel including a liquid crystal light valve and a color filter is an inspection target. However, a liquid crystal light valve before the color filter is attached may be an inspection target. In this case, the inspection image displayed by the liquid crystal light valve is not colored. When this inspection image is captured by a camera, only luminance distribution data not including data related to color can be acquired, so that the liquid crystal light valve can be inspected based on the luminance distribution data.

JP-A-8-145848

  However, in the inspection method of Patent Document 1 as described above, the inspection is performed based only on the luminance distribution data in the inspection image without using the data related to the color of the inspection image. There was a problem that the accuracy could not be realized.

  This is not only a problem of the inspection method described in Patent Document 1 in which inspection is performed based on luminance distribution data acquired by capturing an inspection image, but inspection in which an inspector visually inspects the inspection image for inspection. It was also a problem in the method. That is, since the color of the single color inspection image is uniform throughout, the inspector cannot inspect based on the color of the inspection image, and the inspection is based only on the luminance distribution in the inspection image. I had to do it. Therefore, there has been a problem that sufficient inspection accuracy cannot be realized. In particular, the human eye has high sensitivity to color, but low sensitivity to luminance. Therefore, the visual inspection relying only on the luminance distribution has a problem that inspection accuracy is poor.

  An object of the present invention is to provide an inspection method and an inspection apparatus for an image display apparatus, which can perform an inspection of an image display apparatus with high accuracy based on the color of an inspection image.

  An inspection method for an image display device according to the present invention is an inspection method for an image display device capable of displaying an image, wherein an inspection color image of a predetermined inspection color is displayed on the image display device, and the inspection color is A color image display step of displaying a reference color image of a different reference color on a predetermined reference color image display means, an inspection color image displayed by the image display device, and a reference color image displayed by the reference color image display means Are combined with each other to form one inspection image, and an inspection image forming step is provided.

  In the inspection method having such a configuration, in the color image display step, the inspection color image of the inspection color is displayed on the image display device, and the reference color image of the reference color is displayed on the reference color image display means. Here, the inspection color and the reference color may be any one color different from each other. When a plurality of image display devices and reference color image display means are provided, a plurality of types of inspection colors and reference colors are appropriately selected so as not to overlap each other. In addition, the image display device that displays a colored inspection color image in the color image display step may be a device that can display a colored image by itself, such as a color liquid crystal panel. It may be a light valve that can display a colored image only when colored light is illuminated.

The inspection color image and the reference color image respectively displayed in the color image display step are combined with each other in one inspection image in the inspection image configuration step. The image display device can be inspected based on the inspection image.
Note that there are no defects in the components other than the image display device (particularly, the reference color image display means), and an accurate inspection can be performed by limiting the target to the image display device.

When a defect exists in the image display device, the image display device displays an inspection color image having an abnormal luminance distribution derived from the defect in the color image display step. On the other hand, since there is no defect in the reference color image display means, the reference color image display means displays a reference color image having a normal luminance distribution in the color image display step.
In the subsequent inspection image construction process, the inspection color image and the reference color image are combined into one to form the inspection image. However, since the inspection color image has an abnormal luminance distribution, In each part of the image and the reference color image, the inspection color and the reference color are mixed at an abnormal mixing ratio. As a result, a color display defect (for example, a color unevenness defect) occurs in the inspection image configured in the inspection image configuration process.

  As described above, if there is a defect in the image display apparatus as the inspection target, a color display defect occurs in the inspection image configured through the inspection image configuration process. Therefore, according to the inspection method of the present invention, The inspection of the image display device can be performed with high accuracy based on the color of the inspection image.

  In the image display device inspection method of the present invention, in the color image display step, the luminance of the inspection color image displayed on the image display device and the luminance of the reference color image displayed on the reference color image display means are determined. Are preferably substantially equal to each other.

When the luminance of the reference color image is larger than the luminance of the inspection color image, the inspection color image is abnormal due to a defect in the image display device because the reference color image having a high luminance is mainly determined as the color of the inspection image. Even if a bright luminance distribution occurs, the change in the color of the inspection image derived from the defect is small. Further, when the luminance of the reference color image is smaller than the luminance of the inspection color image, even if an abnormal luminance distribution is generated in the inspection color image due to the defect of the image display device, the defect of the image display device is colored. Since the luminance of the reference color image to be emphasized as a display defect is small, the abnormal luminance distribution of the inspection color image cannot be sufficiently emphasized as a color defect.
On the other hand, according to the inspection method configured as described above, the luminance of the reference color image is substantially equal to the luminance of the inspection color image. When there is a significant luminance distribution, the reference color image can make the abnormal luminance distribution to be emphasized to the maximum to form a color display defect in the inspection image. Therefore, it is possible to accurately detect the defect of the image display device based on the highlighted color display defect without overlooking the defect.

  In the image display device inspection method of the present invention, two reference color image display means are provided, and in the color image display step, the image display device is provided with any one of R color, G color, and B color. One inspection color image is displayed, and the remaining two colors excluding the one color to be displayed on the image display device among the R color, the G color, and the B color are displayed on the two reference color image display means. It is preferable to display each of the reference color images.

  According to the inspection method having such a configuration, in the color image display step, one image display device and two reference color image display means respectively output the inspection color image and the reference color image of each RGB color having substantially the same luminance. Therefore, if there is no defect in the image display device, in the inspection image construction process, RGB is mixed in equal amounts to form an achromatic (white to gray to black) inspection image. At this time, if there is a defect in the image display device, the ratio of RGB color mixture is not 1: 1: 1, so a chromatic color display defect occurs in the inspection image. As described above, if there is a defect in the image display device, a chromatic color display defect occurs in the inspection image that should originally be achromatic, and based on this, the image display device can be accurately detected without overlooking the defect. be able to.

  In the image display device inspection method of the present invention, two reference color image display means are provided, and in the color image display step, a G inspection color image is displayed on the image display device, and It is preferable that the reference color images of R color and B color are respectively displayed on the two reference color image display means.

In general, when one color is generated by mixing three RGB colors, it is known that the mixing amount of the G color among the three RGB colors has the greatest influence on the generated color. That is, when the change in the generated color is observed while changing the mixing amount of any one of the three colors of RGB, the change in the generated color is largest when the mixing amount of the G color is changed.
In the inspection method having the above-described configuration, the RGB image colors are combined to form an inspection image in the inspection image configuration step. At this time, the largest color among the RGB colors is the color of the inspection image. The G color that has an influence is adopted as the color of the inspection color image displayed by the image display device to be inspected. Thereby, when there is a defect in the image display device, the amount of G color mixed in each part of the inspection color image (G color) and the reference color image (R color and B color) is changed in the inspection image forming process. Therefore, the color of the inspection image to be configured changes greatly. That is, by setting the inspection color to G color, it is possible to further emphasize defects in the image display device and configure color display defects in the inspection image. Therefore, according to the inspection method having the above-described configuration, it is possible to accurately detect the defect of the image display device based on the highlighted color display defect without overlooking the defect.

  In the image display device inspection method of the present invention, the image display device can generate a colorless inspection image pattern. In the color image display step, the inspection image pattern is illuminated with light of the inspection color. Preferably, an inspection color image of an inspection color based on the inspection image pattern is displayed on the image display device.

  According to the inspection method having such a configuration, it is possible to inspect an image display device that can display a colored image for the first time when the generated colorless image pattern is illuminated with colored light. An example of such an image display device is a liquid crystal light valve. The liquid crystal light valve generates a colorless image pattern by changing the transmittance of each part. When this colorless image pattern is illuminated with colored light, illumination light is transmitted according to the transmittance of each part, and a colored image based on the colorless image pattern is configured.

  In the image display device inspection method of the present invention, the reference color image display means can generate a colorless reference image pattern having the same configuration as the image display device. In the color image display step, It is preferable that the reference image pattern is illuminated with the light of the reference color, and the reference color image of the reference color based on the reference image pattern is displayed on the reference color image display means.

  According to the inspection method having such a configuration, as the reference color image display unit capable of generating a colorless reference image pattern, the same configuration as that of the image display device can be used. Cost can be reduced.

  In the image display device inspection method of the present invention, a single light source capable of emitting light source light, inspection color light extraction means for extracting light of the inspection color from the light source light, and the reference color from the light source light And a reference color light extraction means for extracting the light of the color, and in the color image display step, the colorless inspection image pattern generated in the image display device is obtained by the inspection color light extracted in the inspection color light extraction means. Illuminating and displaying an inspection color image of an inspection color based on the inspection image pattern on the image display device, and a colorless reference image pattern generated by the reference color image display means is extracted by the reference color light extraction means It is preferable that the reference color image is illuminated with the reference color light and a reference color image of the reference color based on the reference image pattern is displayed on the reference color image display means.

  According to the inspection method of such a configuration, in the color image display step, based on the light of the inspection color and the light of the reference color respectively extracted by the inspection color light extraction unit and the reference color light extraction unit from the light source light of a single light source, The inspection color image and the reference color image can be displayed on the image display device and the reference color image display unit, respectively. At this time, since only one light source is required, it is possible to reduce the manufacturing cost and operating cost of the apparatus used for the inspection.

  In the inspection method for an image display apparatus according to the present invention, the image data relating to the color of the inspection image is obtained by capturing the inspection image configured in the inspection image forming step by an imaging unit having a plurality of imaging pixels. The image data acquisition step of acquiring the image, and when the image display device has no defect, the color of the inspection image configured in the inspection image configuration step is used as a reference color, and the reference color and the individual imaging pixels Performing a color difference data calculation step of calculating color difference data relating to a color difference with respect to the image pickup color based on the image pickup data, and an inspection step of inspecting the image display device based on the color difference data of the individual image pickup pixels. Is preferred.

In the imaging data acquisition step, each part of the inspection image is imaged by each imaging pixel in the imaging means to acquire imaging data. At this time, in particular, data related to the color of each part of the inspection image is acquired by each imaging pixel.
In the subsequent color difference data calculation step, color difference data relating to the color difference between the reference color and the image pickup color of each image pickup pixel is calculated. Here, when there is no defect in the image display device, the image difference of each image pickup pixel substantially matches the reference color, so the color difference becomes substantially zero. Further, when a defect is present in the image display device, a color display defect occurs in the inspection image, and the image pickup color obtained by picking up the display defect portion does not match the reference color, resulting in a color difference. As described above, the color difference data relating to the color difference between the reference color and the imaging color of each imaging pixel is an index for faithfully reproducing the presence or absence of a defect in the image display device.
For this reason, in the subsequent inspection process, it is possible to accurately determine the presence or absence of a defect in the image display device based on the calculated color difference data.
Therefore, according to the inspection method having the above-described configuration, the inspection of the image display apparatus can be performed with high accuracy.

  In the inspection method for an image display device according to the present invention, in the inspection step, the color difference data for the individual imaging pixels is compared with a predetermined color difference data threshold value, and has color difference data exceeding the color difference data threshold value. A counting step for counting imaging pixels, and a count value in the counting step is compared with a predetermined count value threshold, and if the count value exceeds the count value threshold, it is determined that the image display device is defective; It is preferable to perform a defect determination step of determining that the image display device is not defective when the count value does not exceed the count value threshold.

In the counting step, the color difference data for each imaging pixel is compared with a predetermined color difference data threshold value, and the number of imaging pixels having color difference data exceeding the color difference data threshold value is counted. Here, the color difference data threshold value is set as a value suitable for determining whether or not each imaging pixel has captured a color display defect portion in the inspection image. Therefore, the imaging pixels counted in the counting step because they have color difference data exceeding the color difference data threshold are imaging pixels (hereinafter referred to as defective imaging pixels) that are determined to have captured the color display defect portion in the inspection image. is there.
In the subsequent defect determination step, the count value of the defective imaging pixel is compared with a predetermined count value threshold, and if the count value of the defective imaging pixel exceeds the count value threshold, it is determined that the image display device is defective, and the defect imaging is performed. When the count value of the pixel does not exceed the count value threshold, it is determined that the image display device is not defective. Thus, according to the inspection method having the above configuration, an image display is performed based on the number of defective imaging pixels. It is possible to accurately detect a defect in the apparatus.

  An inspection apparatus for an image display apparatus according to the present invention is an inspection apparatus for an image display apparatus capable of displaying an image, displays an inspection color image of a predetermined inspection color on the image display apparatus, and what is the inspection color? Color image display means for displaying reference color images of different reference colors on predetermined reference color image display means, inspection color image displayed by the image display device, and reference color image displayed by the reference color image display means Are combined with each other to form one inspection image, and image forming means for inspection is provided.

  Further, in the inspection apparatus for an image display device of the present invention, the image data relating to the color of the inspection image is obtained by capturing the inspection image configured in the inspection image forming unit by the imaging unit having a plurality of imaging pixels. Imaging data acquisition means for acquiring color difference data calculation means for calculating color difference data relating to a color difference between a predetermined reference color and the imaging color of each individual imaging pixel based on the imaging data; and It is preferable that inspection means for inspecting the image display device based on color difference data is provided.

  Since the inspection apparatus of the present invention configured as described above has a structure for carrying out the above-described inspection method of the present invention, the same functions and effects as the inspection method of the present invention can be achieved.

  In the inspection apparatus for an image display apparatus according to the present invention, the image display apparatus can generate a colorless inspection image pattern, and is detachable at a light illumination position of the inspection color. Preferably, the means generates an inspection image pattern on the image display device arranged at the illumination position of the inspection color light, and displays an inspection color image of the inspection color based on the inspection image pattern.

  According to the inspection apparatus having such a configuration, in order to inspect a plurality of image display apparatuses, it is only necessary to sequentially arrange each inspection object image display apparatus at the illumination position of the inspection color light. This image display device can be inspected easily and quickly.

Next, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a diagram showing an inspection apparatus according to the first embodiment of the present invention.
The inspection apparatus includes a projection apparatus 1 that projects a predetermined inspection image and a screen 2 that displays the inspection image projected by the projection apparatus 1.

FIG. 2 is a diagram showing an internal configuration of the projection apparatus 1.
The projection apparatus 1 includes a single light source 11, four dichroic mirrors 121, 122, 123, and 124, two reflection mirrors 131 and 132, three liquid crystal light valves 14R, 14G, and 14B, and projection. And a lens 15.

The light source 11 is constituted by a high-pressure mercury lamp or the like, and can emit light source light having a continuous spectrum.
The dichroic mirrors 121 to 124 are mirrors that reflect only light of a specific color (specific wavelength range) and transmit other light, respectively. Specifically, the dichroic mirror 121 reflects only R-color light, the dichroic mirror 122 reflects only G-color light, the dichroic mirror 123 reflects only G-color light, and the dichroic mirror 124 reflects R-color. Only the light of the mixed color (yellow) of G and G is reflected.
The reflection mirrors 131 and 132 are mirrors that reflect light, respectively.

Each of the liquid crystal light valves 14R, 14B, and 14G can generate a colorless image pattern by changing the light transmittance based on a signal input from a signal input unit (not shown).
The liquid crystal light valve 14 </ b> R is disposed at a position Pr where the R light generated by the light source light reflected by the dichroic mirror 121 is illuminated via the reflection mirror 131. Due to this arrangement, the colorless image pattern generated by the liquid crystal light valve 14R is illuminated with R light, and the liquid crystal light valve 14R displays an R color image based on the image pattern.
The liquid crystal light valve 14G is arranged at a position Pg where the light of G color generated by the light source light (mixed color of G and B) transmitted through the dichroic mirror 121 being reflected by the dichroic mirror 122 is illuminated. Is done. Due to this arrangement, the colorless image pattern generated by the liquid crystal light valve 14G is illuminated with G-color light, and the liquid crystal light valve 14G displays a G-color image based on the image pattern.
The liquid crystal light valve 14B is disposed at a position Pb where the light of B color generated by the light source light passing through the dichroic mirror 121 and the dichroic mirror 122 is illuminated. Due to this arrangement, the colorless image pattern generated by the liquid crystal light valve 14B is illuminated with B light, and the liquid crystal light valve 14B displays a B color image based on the image pattern.

  Each of the liquid crystal light valves 14R, 14G, and 14B generates a colorless image pattern and has the same configuration. The colors (RGB) displayed by the liquid crystal light valves 14R, 14G, and 14B are arranged positions Pr, Pg, and Pb, that is, which color liquid crystal light valve is arranged on the optical path of illumination light of any color. It depends on.

Now, the R color image displayed by the liquid crystal light valve 14R and the G color image displayed by the liquid crystal light valve 14G are combined by the dichroic mirror 123. Furthermore, the mixed color (yellow) image of the R color and the G color is synthesized by the dichroic mirror 124 with the B color image displayed by the liquid crystal light valve 14B and reflected by the reflection mirror 132.
The combined image of RGB colors configured as described above is projected onto the screen 2 via the projection lens 15.

  The inspection target of the inspection performed by the inspection apparatus having the above configuration is the liquid crystal light valve 14G disposed at the position Pg. Therefore, the liquid crystal light valve 14G constitutes an image display device as an inspection object of the inspection method of the present invention. On the other hand, the liquid crystal light valves 14R and 14B constitute reference color image display means of the present invention, and are not inspection targets in the inspection. Here, in order to appropriately inspect the liquid crystal light valve 14G as the inspection target, the liquid crystal light valves 14R and 14B that are not the inspection target are those that have been confirmed to be free of defects in advance. These defect-free liquid crystal light valves 14R and 14B are fixedly arranged at positions Pr and Pb, respectively, and the same one is used throughout the inspection. In addition, a liquid crystal light valve to be inspected can be attached to and detached from the position Pg. When there are a plurality of liquid crystal light valves (14G) to be inspected at the time of inspection, each of these liquid crystal light valves (14G) to be inspected ( 14G) are sequentially arranged at the position Pg, and the individual liquid crystal light valves (14G) to be inspected are sequentially inspected.

  In the inspection of the liquid crystal light valve 14G, an image of G color (inspection color) is displayed on the liquid crystal light valve 14G as an inspection target image display device, and R image and B image of R color and B color (reference color) are displayed. Are displayed on the liquid crystal light valves 14R and 14B as reference color image display means, the G image displayed by the liquid crystal light valve 14G, the R image displayed by the liquid crystal light valves 14R and 14B, and An inspection image construction process is performed in which the B images are combined with each other to form one inspection image.

  In the color image display step, predetermined equal signals are simultaneously input to the liquid crystal light valves 14R, 14G, and 14B by a signal input means (not shown). Since the input signals are equal to each other and the transmittances of the three liquid crystal light valves 14R, 14G, and 14B are changed to be equal to each other, the liquid crystal light valves 14R, 14G, and 14B generate the same image pattern. Here, the image pattern generated by the liquid crystal light valve 14G as the inspection target image display device of the present invention corresponds to the inspection image pattern of the present invention, and the liquid crystal light valve 14R as the reference color image display means of the present invention. , 14B corresponds to the reference image pattern in the present invention. Therefore, in the present embodiment, the inspection image pattern (generated by the liquid crystal light valve 14G) and the two reference image patterns (generated by the liquid crystal light valves 14R and 14B) in the present invention are the same.

  Each of the image patterns generated by the liquid crystal light valves 14R, 14G, and 14B is illuminated with light of R, G, and B colors, and the liquid crystal light valves 14R, 14G, and 14B are R, G, and G, respectively. Color and B color images are displayed. The G image displayed by the liquid crystal light valve 14G as the inspection target image display device of the present invention corresponds to the inspection color image of the present invention, and the liquid crystal light valve 14R as the reference color image display means of the present invention and The R color and the B image displayed by 14B correspond to the reference color image of the present invention. Here, the dichroic mirror 122 extracts the inspection color (G color) light from the light source light, and illuminates the colorless inspection image pattern generated in the image display device (liquid crystal light valve 14G). The dichroic mirrors 121 and 122 extract the light of the reference colors (R color and B color) from the light source light, and are generated in the reference color image display means (liquid crystal light valves 14R and 14B). It functions as the reference color light extraction means of the present invention for illuminating a colorless reference image pattern.

  Since the image patterns based on the transmittances generated by the liquid crystal light valves 14R, 14G, and 14B are the same, the brightness of the R image, the G image, and the B image displayed by the liquid crystal light valves 14R, 14G, and 14B, respectively. They are almost equal to each other. Therefore, the luminance of the inspection color image (G image) of the present invention and the luminance of the reference color image (R image and B image) of the present invention are substantially equal to each other.

  In addition, each signal input from the signal input means to each liquid crystal light valve 14R, 14G, 14B is set so as to uniformly maximize the transmittance of each liquid crystal light valve 14R, 14G, 14B over the entire surface. ing. Therefore, the R image, G image, and B image displayed by each of the liquid crystal light valves 14R, 14G, and 14B have the maximum luminance uniformly over the entire surface.

  In the inspection image construction process, the R image, the G image, and the B image displayed by the liquid crystal light valves 14R, 14G, and 14B are combined into one inspection image by the dichroic mirror 124, and the screen 2 is connected via the projection lens 15. Projected on. Here, the dichroic mirror 124 includes the inspection color image (G image) displayed by the liquid crystal light valve 14G as the inspection target image display device of the present invention, the liquid crystal light valve 14R as the reference color image display means of the present invention, and The reference color images (R image and B image) displayed by 14B are combined with each other to function as inspection image constructing means of the present invention that forms one inspection image.

  At this time, the color of the inspection image projected on the screen 2 is white because R color having the maximum luminance, G color having the maximum luminance, and B color having the maximum luminance are generated in an equal amount. In addition, since the brightness of each of the R image, the G image, and the B image is uniform over the entire surface, the brightness of the white inspection image is also uniform over the entire surface (however, the liquid crystal light valve to be inspected) 14G has no defects).

  If the liquid crystal light valve 14G to be inspected has a defect, the transmittance in the liquid crystal light valve 14G is not uniform, and thus the luminance unevenness occurs in the G image displayed by the liquid crystal light valve 14G. Then, when the R image, the G image (including luminance unevenness), and the B image are combined into one inspection image by the dichroic mirror 124, the G color has the desired color mixture ratio in the portion where the luminance unevenness occurs. Color mixing is not performed, and the RGB color mixing ratio in this portion is not 1: 1: 1. For this reason, the inspection image projected on the screen 2 has a color unevenness defect caused by the brightness unevenness included in the G image. Specifically, when the luminance unevenness included in the G image has a luminance larger than the intended luminance, the mixing ratio of G color is larger than the intended mixing ratio in the case of RGB color mixing. In the inspection image, the G color irregularity defect occurs, and when the luminance irregularity included in the G image has a luminance smaller than the intended luminance, the mixing ratio of the G color is changed in the RGB color mixing. Since it becomes smaller than the intended mixing ratio, an uneven color defect of the mixed color of R color and B color (red purple) occurs in the inspection image.

  The inspection of the liquid crystal light valve 14G to be inspected is performed by the inspector viewing the inspection image projected on the screen 2 (see FIG. 1).

<Effects of First Embodiment>
According to the first embodiment as described above, the following effects can be obtained.
If there is no defect in the liquid crystal light valve 14G to be inspected, the entire surface of the inspection image has a uniform color (white). If there is a defect in the liquid crystal light valve 14G to be inspected, the inspection image has G color or red Since the purple uneven color defect occurs, the inspector can accurately detect the defect of the liquid crystal light valve 14G without overlooking the defect.

  Since each of the liquid crystal light valves 14R, 14G, and 14B displays an R image, a G image, and a B image having substantially the same luminance, the abnormal luminance of the G image is caused by a defect in the liquid crystal light valve 14G to be inspected. In the case where there is a distribution, the R image and the B image can enhance the abnormal luminance distribution in the G image to the maximum to form a G-color or red-purple color unevenness defect in the inspection image. Therefore, it is possible to accurately detect the defect of the liquid crystal light valve 14G to be inspected based on the uneven color defect that is emphasized in the inspection image.

  In the color image display process, each of the liquid crystal light valves 14R, 14G, and 14B displays RGB images having substantially the same brightness. Therefore, if the liquid crystal light valve 14G to be inspected is defective, the liquid crystal light valve 14G is essentially white (nothing). In the inspection image that should be chromatic), a color irregularity defect of G color or magenta (chromatic color) occurs, and based on this, it is possible to accurately detect the defect of the liquid crystal light valve 14G to be inspected. .

  In the inspection image construction process, RGB color images are synthesized to form a white inspection image. At this time, among the RGB colors, the G color that has the greatest influence on the color of the inspection image is selected as the inspection target. It is displayed on the liquid crystal light valve 14G. Thereby, the defect in the liquid crystal light valve 14G to be inspected can be more emphasized, and the uneven color defect in the inspection image can be configured. Accordingly, it is possible to accurately detect the defect of the liquid crystal light valve 14G to be inspected based on the emphasized color unevenness defect without overlooking the defect.

  As the reference color image display means of the present invention, the liquid crystal light valves 14R and 14B having the same configuration as the liquid crystal light valve 14G as the inspection target image display apparatus of the present invention can be used. Can be reduced.

  In the color image display step, an image of each RGB color can be displayed on each liquid crystal light valve 14R, 14G, 14B based on the light of each RGB color extracted by the dichroic mirrors 121 and 122 from the light source of the single light source 11, respectively. it can. At this time, since only one light source 11 is required, the manufacturing cost and operating cost of the inspection apparatus can be reduced.

  When inspecting a plurality of liquid crystal light valves, it is only necessary to sequentially arrange each of the liquid crystal light valves to be inspected at the position Pg, so that the inspection can be performed easily and quickly, and the inspection cost can be reduced. it can.

  In the color image display step, equal signals are simultaneously input to the liquid crystal light valves 14R, 14G, and 14B by signal input means (not shown) in order to cause the liquid crystal light valves 14R, 14G, and 14B to generate the same image pattern. Therefore, the input signal can be simplified and the inspection cost can be reduced.

  Since the inspection image is white, when the liquid crystal light valve 14G to be inspected has a defect, the G color or red-purple color unevenness defect that appears in the inspection image stands out. Therefore, it is difficult to overlook the uneven color defect, and the inspector can accurately detect the defect of the liquid crystal light valve 14G to be inspected.

Second Embodiment
Next, the inspection apparatus according to the second embodiment of the present invention will be described using FIGS. 3 to 11 with emphasis on differences from the inspection apparatus according to the first embodiment.
For simplification of description, the same or corresponding components in the inspection apparatus of the first embodiment as those in the inspection apparatus of the second embodiment are the same as those in the first embodiment. The same reference numerals as the reference numerals are attached, and the description thereof is omitted or simplified.

FIG. 3 is a view showing an inspection apparatus according to the second embodiment of the present invention.
In addition to the projection apparatus 1 and the screen 2 similar to those in the first embodiment, the inspection apparatus controls the 3CCD camera 3 that captures the inspection image projected on the screen 2 and controls the projection apparatus 1 and the 3CCD camera 3 for projection. And a control unit 4 for inspecting the liquid crystal light valve 14G to be inspected incorporated in the apparatus 1.

  The 3CCD camera 3 is an imaging unit having a large number of 3CCD camera pixels (imaging pixels) arranged on the imaging surface. Each 3CCD camera pixel (hereinafter abbreviated as camera pixel) includes a prism that separates incident light into RGB light, an R color light receiving CCD that receives light of each RGB color separated by the prism, and a G color light receiving CCD. A total of three CCDs (Charged Coupled Devices), which are a CCD and a B color light receiving CCD, are configured. The RGB color light receiving CCDs receive R color light, G color light, and B color light included in incident light, and output respective luminances. Here, when the luminances of the R color light, the G color light, and the B color light are set as R, G, and B, respectively, the output of each camera pixel can be expressed as a set of luminances (R, G, B) of each RGB color light. .

  The control unit 4 includes a color image display unit 41, an imaging data acquisition unit 42, a color difference data calculation unit 43, and an inspection unit 44.

The color image display means 41 displays the R image, the G image, and the B image on the liquid crystal light valves 14R, 14G, and 14B, respectively.
The imaging data acquisition means 42 captures an image projected on the screen 2 by the 3CCD camera 3 and acquires imaging data related to the color of the image.
The color difference data calculation unit 43 calculates color difference data related to a color difference between a predetermined reference color and the image pickup color of each camera pixel based on the image pickup data acquired by the image pickup data acquisition unit 42.
The inspection unit 44 includes a counting unit 441 and a defect determination unit 442, and inspects the liquid crystal light valve 14G to be inspected based on the color difference data for each camera pixel.

The counting means 441 compares the color difference data for each camera pixel with a predetermined color difference data threshold value, and counts camera pixels having color difference data exceeding the color difference data threshold value.
The defect determination unit 442 compares the count value of the camera pixel counted by the counting unit 441 with a predetermined count value threshold, and determines that the liquid crystal light valve 14G is defective when the count value exceeds the count value threshold. If the count value does not exceed the count value threshold, it is determined that the liquid crystal light valve 14G is not defective.

  Next, the inspection of the liquid crystal light valve performed by the inspection apparatus according to the second embodiment having the above-described configuration will be described with reference to the flowcharts of FIGS. 4 and 5.

Before the actual inspection of the liquid crystal light valve 14G, the control unit 4 acquires various reference data used for the inspection (S1: S is a process, the same applies hereinafter).
FIG. 5 shows a specific processing flow in S1. In S1, three liquid crystal light valves that have been confirmed to be free of defects in advance are arranged at positions Pr, Pg, and Pb in the projection apparatus 1, respectively.

  The color image display means 41 inputs a predetermined reference R image display signal to each of the liquid crystal light valves 14R, 14G, 14B via a signal input means (not shown). Here, the reference R image display signal is a signal for causing the projection device 1 to project an R-color reference R image having an arbitrary uniform luminance over the entire surface. This is a signal for making the transmittance of the light valve 14R uniform at an arbitrary value over the entire surface and uniformly minimizing the transmittance of the liquid crystal light valves 14G and 14B over the entire surface. Then, the reference R image projected from the projection device 1 is displayed on the screen 2 (S11).

  Subsequently, the tristimulus values (Xr, Yr, Zr) of the reference R image displayed on the screen 2 are measured by a color luminance meter or the like (S12). Here, since the reference R image is displayed by the liquid crystal light valves 14R, 14G, and 14B without any defects, the tristimulus values are uniform over the entire surface. Therefore, it is sufficient to measure the tristimulus values (Xr, Yr, Zr) at an arbitrary point in the reference R image. In this embodiment, as shown in FIG. 6A, tristimulus values are measured at the center point (x0, y0) in the reference R image. As shown in FIG. 6 (B), tristimulus values are measured at nine points (x1, y1) to (x9, y9) or a plurality of other points in the reference R image, and the average value is calculated. The tristimulus values (Xr, Yr, Zr) of the reference R image may be adopted.

  FIG. 7 shows a reference R image and tristimulus values (Xr, Yr, Zr) measured at the center point (x0, y0). As shown in this figure, (Xr, Yr, Zr) = (0.66137, 0.28740, 0.00214). The tristimulus values (Xr, Yr, Zr) measured here are stored by the color difference data calculation means 43, and are read out and used in the later inspection of the liquid crystal light valve.

  Subsequently, the color image display means 41 inputs a predetermined reference G image display signal to each of the liquid crystal light valves 14R, 14G, and 14B via a signal input means (not shown). Here, the reference G image display signal is a signal for causing the projection apparatus 1 to project a G reference G image having an arbitrary uniform luminance over the entire surface. This is a signal that makes the transmittance of the light valve 14G uniform at an arbitrary value over the entire surface and minimizes the transmittance of the liquid crystal light valves 14B and 14R uniformly over the entire surface. Then, the reference G image projected from the projection device 1 is displayed on the screen 2 (S13).

Subsequently, the tristimulus values (Xg, Yg, Zg) of the reference G image displayed on the screen 2 are measured by a color luminance meter or the like (S14).
FIG. 8 shows an example of the reference G image and tristimulus values (Xg, Yg, Zg) measured at the center point (x0, y0). As shown in this figure, (Xg, Yg, Zg) = (0.33365, 0.94195, 0.04987). The tristimulus values (Xg, Yg, Zg) measured here are stored by the color difference data calculation means 43, and are read out and used in the later inspection of the liquid crystal light valve.

  Subsequently, the color image display means 41 inputs a predetermined reference B image display signal to each of the liquid crystal light valves 14R, 14G, and 14B via a signal input means (not shown). Here, the reference B image display signal is a signal for causing the projection device 1 to project a reference B image of B color having an arbitrary uniform luminance over the entire surface. This is a signal for making the transmittance of the light valve 14B uniform at an arbitrary value over the entire surface and uniformly minimizing the transmittance of the liquid crystal light valves 14R and 14G over the entire surface. Then, the reference B image projected from the projection device 1 is displayed on the screen 2 (S15).

Subsequently, the tristimulus values (Xb, Yb, Zb) of the reference B image displayed on the screen 2 are measured by a color luminance meter or the like (S16).
FIG. 9 shows an example of the reference B image and tristimulus values (Xb, Yb, Zb) measured at the center point (x0, y0). As shown in this figure, (Xb, Yb, Zb) = (0.33554, 0.14314, 1.38680). The tristimulus values (Xb, Yb, Zb) measured here are stored by the color difference data calculation means 43, and are read out and used in the subsequent inspection of the liquid crystal light valve.

  Subsequently, the color image display means 41 inputs a predetermined reference W image display signal to each of the liquid crystal light valves 14R, 14G, and 14B via a signal input means (not shown). Here, the reference W image display signal is a signal for causing the projector 1 to project a white (W color) reference W image having an arbitrary uniform luminance over the entire surface. Is a signal for making the transmittance of each of the liquid crystal light valves 14R, 14G, and 14B uniform at an arbitrary value over the entire surface. Then, the reference W image projected from the projection device 1 is displayed on the screen 2 (S17).

Subsequently, the tristimulus values (Xw, Yw, Zw) of the reference W image displayed on the screen 2 are measured by a color luminance meter or the like (S18).
FIG. 10 shows an example of the reference W image and tristimulus values (Xw, Yw, Zw) measured at the center point (x0, y0). As shown in this figure, (Xw, Yw, Zw) = (1.116826, 1.186624, 1.21772). The tristimulus values (Xw, Yw, Zw) measured here are stored by the color difference data calculation means 43, and are read out and used in the subsequent inspection of the liquid crystal light valve.

  Subsequently, the imaging data acquisition unit 42 captures the reference W image displayed on the screen 2 with the 3 CCD camera 3. At this time, each camera pixel in the 3CCD camera 3 outputs the received light luminance (Rw, Gw, Bw) of each RGB color. Here, since the brightness of the reference W image is uniform over the entire surface, the outputs (Rw, Gw, Bw) of all camera pixels are equal to each other. Thus, there is no difference in output (Rw, Gw, Bw) between the camera pixels, and the imaging data acquisition means 42 selects any one camera pixel and outputs the output (Rw, Gw, Bw). Obtained as reference W image imaging data representing the light emission luminance of the reference W image (S19).

FIG. 10 shows an example of the reference W image capturing data (Rw, Gw, Bw). As shown in this figure, (Rw, Gw, Bw) = (230, 231, 233). The reference W image capturing data (Rw, Gw, Bw) acquired here is stored by the color difference data calculation means 43, and is read out and used in the subsequent inspection of the liquid crystal light valve.
Note that the imaging data acquisition unit 42 instead of acquiring the output of any one camera pixel as the reference W image imaging data (Rw, Gw, Bw), uses the average value of the outputs of the plurality of camera pixels as the reference W image imaging. You may acquire as data (Rw, Gw, Bw).

  After completion of the reference data acquisition step (S1) as described above, the liquid crystal light valve is actually inspected.

  First, a liquid crystal light valve to be inspected is arranged at a position Pg (see FIG. 2) (S2). Here, since the liquid crystal light valve that has been confirmed to be free of defects in S1 is disposed at the position Pg, in S2, the liquid crystal light valve without defects is replaced with a liquid crystal light valve to be inspected. Is called. It should be noted that the liquid crystal light valve having no defect arranged at the positions Pr and Pb in S1 is fixedly arranged as it is after S2, and is used as the reference color image display means of the present invention.

  Subsequently, the color image display means 41 inputs a signal identical to the reference W image display signal in S17 to each of the liquid crystal light valves 14R, 14G, and 14B via a signal input means (not shown), thereby obtaining a predetermined inspection image. The inspection image is displayed on the screen 2 via the projection lens 15 in the projection apparatus 1 (S3). Since the input signal is the same as the reference W image display signal, if there is no defect in the liquid crystal light valve 14G to be inspected, the inspection image displayed on the screen 2 completely matches the reference W image displayed in S17. To do. On the other hand, if the liquid crystal light valve 14G to be inspected has a defect, the inspection image displayed on the screen 2 has a G-color or red-purple color unevenness defect (see the first embodiment).

  Subsequently, the imaging data acquisition unit 42 captures the inspection image displayed on the screen 2 with the 3CCD camera 3. At this time, each camera pixel in the 3CCD camera 3 outputs RGB received light intensity (R, G, B). Outputs (R, G, B) of individual camera pixels are acquired by the control unit 4 as inspection image imaging data (S4: imaging data acquisition process).

FIG. 11 shows an example of inspection image pickup data (R, G, B).
This figure is composed of three tables (A), (B), and (C) representing the R light reception luminance, G light reception luminance, and B light reception luminance of each camera pixel, respectively. The data arranged at the same coordinates in each table represents the R light reception luminance, G light reception luminance, and B light reception luminance of the same camera pixel, respectively. For example, the R light reception luminance of the camera pixel (camera pixel surrounded by a thick line) arranged at the coordinates (5, 5) is 229, the G light reception luminance is 230, and the B light reception luminance is 232.

Subsequently, the color difference data calculation means 43 obtains tristimulus value data (Xr, Yr, Zr), (Xg, Yg, Zg), (Xb, Yb,) acquired in advance in the reference data acquisition step (S1). Zb), (Xw, Yw, Zw), the reference W image capturing data (Rw, Gw, Bw), and the inspection image capturing data (R, G, B) acquired in S4 Color difference data ΔE ^* ab relating to the color difference between the color of the W image (reference color) and the captured color of each camera pixel is calculated (S5: color difference data calculating step).

First, the color difference data calculation unit 43 selects one camera pixel of interest for calculating color difference data.
The color difference data calculation unit 43 reads out the light reception luminances (R, G, B) of the selected camera pixel of interest from the inspection image pickup data (see FIG. 11) and substitutes them into the following equation (1).

The three numerical values (α, β, γ) calculated by the equation (1) are related to the tristimulus values of the light received by the camera pixel of interest. Note that each matrix element of the 3 × 3 square matrix on the right side of Equation (1) is tristimulus value data acquired in advance in S1.
Subsequently, the color difference data calculating unit 43 substitutes (α, β, γ) calculated by the equation (1) into the following known equation (2) relating to the L ^* a ^* b ^* color system.

The three numerical values (L ^* ₁ , a ^* ₁ , b ^* ₁ ) calculated by the expression (2) have a meaning as an imaging color index of the camera pixel of interest.

Subsequently, the color difference data calculation unit 43 performs the same arithmetic processing as the formulas (1) and (2) for the reference W image imaging data (Rw, Gw, Bw). That is, (L ^* ₂ , a ^* ₂ , b ^* ₂ ) is calculated by the following formulas (3) and (4).

The three numerical values (L ^* ₂ , a ^* ₂ , b ^* ₂ ) calculated by the equation (4) have a meaning as an index of the color (reference color) of the reference W image.

Subsequently, the color difference data calculating unit 43 calculates (L ^* ₁ , a ^* ₁ , b ^* ₁ ) according to the equation (2) and (L ^* ₂ , a ^* ₂ , b ^* ₂ ) is substituted into the following equation (5) to calculate color difference data ΔE ^* ab.

As described above, after calculating the color difference data ΔE ^* ab for one target camera pixel, the color difference data calculating unit 43 switches the target camera pixel and sequentially calculates the color difference data ΔE ^* ab as described above. go. Thus, in S5, the color difference data ΔE ^* ab is calculated for all camera pixels.

The color difference data ΔE ^* ab calculated by Expression (5) is data relating to the color difference between the color of the reference W image (reference color) and the captured color of each camera pixel. Therefore, if there is no defect in the liquid crystal light valve 14G to be inspected and the inspection image completely matches the reference W image, ΔE ^* ab is zero for all camera pixels. On the contrary, when the liquid crystal light valve 14G to be inspected has a defect and the inspection image does not coincide with the reference W image, the camera pixel that captures the uneven color defect portion of the inspection image resulting from the defect. The color difference data ΔE ^* ab for is not zero.

Subsequently, the counting means 441, the color difference data Delta] E ^* ab for the individual camera pixels, respectively, with a predetermined color difference data threshold Delta] E ^* ab _0, the color difference data Delta] E exceeding the color difference data threshold ΔE ^* ab ₀ ^* The camera pixels having ab are counted (S6: counting step).

Here, the color difference data threshold value ΔE ^* ab ₀ determines, for each camera pixel, whether or not an uneven color defect portion of an inspection image generated due to a defect existing in the liquid crystal light valve 14G to be inspected is captured. It is set as a value suitable for That is, the camera pixel ^{(ΔE * ab <ΔE * ab} 0) having a color difference data Delta] E ^* ab no greater than the color-difference data threshold Delta] E ^* ab ₀ has to have captured the normal display area is not the irregular color defect portion of the test image is determined, also the camera pixel ^{(ΔE * ab ≧ ΔE * ab} 0) having a color difference data Delta] E ^* ab of more than chrominance data threshold Delta] E ^* ab ₀ is defective imaging camera pixels of the captured color unevenness defect portion of the test image Is determined. The counting means 441 counts such defective imaging camera pixels.

  If the count value N of the defective imaging camera pixel is large, there are many color uneven defect portions in the inspection image displayed on the screen 2, and therefore there is a high possibility that a defect exists in the liquid crystal light valve 14G to be inspected. . Further, if the count value N of the defective imaging camera pixel is small, there is almost no uneven color defect portion in the inspection image displayed on the screen 2, so there is a possibility that the liquid crystal light valve 14G to be inspected has a defect. small.

Subsequently, the defect determination unit 442 compares the count value N of the defective imaging camera pixel counted by the counting unit 441 with a predetermined count value threshold value N _0, and the count value N of the defective imaging camera pixel is the count value threshold value N _0. It is determined whether it is less than (N <N ₀ ) (S7: defect determination step).
Here, the count value threshold N ₀ is a threshold for determining whether or not a defect exists in the liquid crystal light valve 14G to be inspected.

When the count value N of the defective imaging camera pixel is less than the count value threshold N ₀ (N <N ₀ ) (Yes), the defect determination unit 442 determines that the liquid crystal light valve 14G to be inspected is not defective (S81). ). When the count value N of the defective imaging camera pixel is equal to or greater than the count value threshold N ₀ (N ≧ N ₀ ) (No), the defect determination unit 442 determines that the liquid crystal light valve 14G to be inspected is defective. (S82).

As described above, when the inspection for one liquid crystal light valve 14G to be inspected is completed, the control unit 4 determines whether or not all the liquid crystal light valves to be inspected have been inspected (S9).
When there is a liquid crystal light valve that has not been inspected yet (No), the control unit 4 repeatedly performs the inspections of S2 to S81 and S82 for these liquid crystal light valves. Then, after all the liquid crystal light valves are inspected (Yes), the inspection ends.

Next, processing in each process of S5 to S81 and S82 in the flowchart of FIG. 4 will be described with a specific example.
In addition, as the various reference data used in the calculation of the color difference data ΔE ^* ab (S5), the data shown in FIGS. 7 to 10 is used, and as the inspection image pickup data (R, G, B), The one shown in FIG. 11 is used.

In S5, first, the color difference data calculation unit 43 selects one camera pixel of interest for calculating the color difference data ΔE ^* ab. Here, it is assumed that the camera pixel surrounded by a thick line in FIG. 11 is selected as the camera pixel of interest.
The color difference data calculation means 43 substitutes each color light reception luminance (R, G, B) = (229, 230, 232) of the camera pixel of interest into the equation (1).

Note that “E” in Equation 6 represents a power of 10 (the same applies hereinafter).
The three numerical values (α, β, γ) calculated by the equation (6) are related to the tristimulus values of the light received by the camera pixel of interest.
Subsequently, the color difference data calculating unit 43 substitutes (α, β, γ) calculated by the equation (6) into the equation (2).

The three numerical values (L ^* ₁ , a ^* ₁ , b ^* ₁ ) calculated by the equation (7) have a meaning as an imaging color index of the camera pixel of interest.

Subsequently, the color difference data calculating unit 43 performs the same arithmetic processing as in the equations (6) and (7) for the reference W image imaging data (Rw, Gw, Bw) = (230, 231, 233) in FIG. I do. That is, (L ^* ₂ , a ^* ₂ , b ^* ₂ ) is calculated by the following formulas (8) and (9).

The three numerical values (L ^* ₂ , a ^* ₂ , b ^* ₂ ) calculated by the equation (9) have a meaning as an index of the color (reference color) of the reference W image.

Subsequently, the color difference data calculation means 43 (L ^* ₁ , a ^* ₁ , b ^* ₁ ) calculated by the equation (7) and (L ^* ₂ , a ^* ₂ ^,. b ^* ₂ ) is substituted into the equation (5) to calculate the color difference data ΔE ^* ab.

As described above, after calculating the color difference data ΔE ^* ab for one target camera pixel, the color difference data calculating unit 43 switches the target camera pixel and sequentially calculates the color difference data ΔE ^* ab as described above. go.

In subsequent S6, counting means 441, the color difference data Delta] E ^* ab for the individual camera pixels, respectively, compared to the color difference data threshold Delta] E ^* ab _0, the color difference data Delta] E ^* ab of more than the color difference data threshold Delta] E ^* ab ₀ Count the camera pixels with
Here, the color difference data threshold is set as ΔE ^* ab ₀ = 5.

The color difference data for the camera pixel of interest in FIG. 11 having a received light luminance of (R, G, B) = (229, 230, 232) is calculated as ΔE ^* ab = 1.050 by Equation (10), and ΔE ^{Since *} ab = 1.050 <5 = ΔE ^* ab _0, it is determined that the camera pixel of interest has captured a normal display portion that is not a nonuniform color defect portion of the inspection image, and is not counted by the counting unit 441.

Further, for example, the color difference data for other camera pixels having a light receiving luminance of (R, G, B) = (229, 256, 232) is ΔE ^* ab = as in the equations (6) to (10). Since 6.049 is calculated and ΔE ^* ab = 6.049> 5 = ΔE ^* ab ₀ , this camera pixel is determined to be a defective imaging camera pixel that has captured the color unevenness defect portion of the inspection image and counted. Counted by means 441.
This camera pixel has a G light receiving luminance (256) that is remarkably large, and picks up a G color unevenness defect portion that occurs in the inspection image due to a defect in the liquid crystal light valve 14G to be inspected. It is suggested that this is a camera pixel.

Continued In S7, the defect determining unit 442, the count value N of the defective imaging camera pixels counted by the counting means 441 compares the count value threshold N _0, the count value N is less than the count value threshold N ₀ of defective imaging camera pixel It is determined whether or not (N <N ₀ ).
Here, the count value threshold is set as N ₀ = 1000.

When the count value of the defective imaging camera pixel is less than 1000 (N <N ₀ ), the defect determination unit 442 determines that the liquid crystal light valve 14G to be inspected is not defective (S81). When the count value of the defective imaging camera pixel is 1000 or more (N ≧ N ₀ ), the defect determination unit 442 determines that the liquid crystal light valve 14G to be inspected is defective (S82).

<Effects of Second Embodiment>
According to the second embodiment as described above, the following effects can be obtained.
Since the color difference data relating to the color difference between the color of the reference W image (reference color) and the captured color of each camera pixel has a meaning as an index to faithfully reproduce the presence or absence of defects in the liquid crystal light valve 14G to be inspected. Based on the color difference data, the presence or absence of a defect in the liquid crystal light valve 14G to be inspected can be accurately determined.

  The inspection unit 44 includes a counting unit 441 and a defect determination unit 442. Based on the number of defect imaging camera pixels counted by the counting unit 441, the defect determination unit 442 detects defects in the liquid crystal light valve 14G to be inspected. Presence / absence can be accurately determined.

  Since the liquid crystal light valve 14G to be inspected can be automatically inspected under the control of the control unit 4, the inspection accuracy does not vary as in the visual inspection by the inspector, and the inspection is performed with stable accuracy. It can be performed.

<Modification>
The present invention is not limited to the embodiment described above, and any modification of this embodiment within the scope that can achieve the object of the present invention is included in the technical scope of the present invention.

  For example, in each of the above embodiments, the liquid crystal light valve is an inspection target, but the inspection target is not limited to the liquid crystal light valve, and various image display devices that can display colored images in the color image display process are also inspected. It is possible. Such an image display device may be a device that can display a colored image only when colored light is illuminated, such as the liquid crystal light valve of each of the above embodiments. The liquid crystal panel may be capable of displaying a colored image by itself.

  In each of the above embodiments, one liquid crystal light valve 14G is provided as the inspection target image display device of the present invention. However, a plurality of inspection target image display devices are provided to simultaneously display two or more inspection color images. By combining these with a reference color image, an image for inspection may be configured to inspect a plurality of image display devices at the same time.

  In each of the above embodiments, the two liquid crystal light valves 14R and 14B are provided as the reference color image display means of the present invention. However, only one reference color image display means may be provided, or three or more reference color image display means may be provided. May be.

  In each of the above embodiments, the G image is used as the inspection color image of the present invention, and the R image and the B image are used as the reference color image of the present invention. However, the colors of the inspection color image and the reference color image are combined. In short, the color of the inspection color image and the color of the reference color image need only be different from each other.

  In each of the embodiments, the color of the inspection image is white. However, the color of the inspection image is determined by the combination of the inspection color image and the reference color image, and is not limited to white.

  In each of the above embodiments, the inspection color image of the present invention and the RGB images as the reference color image are synthesized by the dichroic mirror 124 to form one inspection image. Is not limited to such a method. For example, an inspection image may be configured by combining an inspection color image and a reference color image into one using an appropriate optical element other than a dichroic mirror in the same manner as in the above embodiments. One image for inspection may be formed by combining individual image data obtained by individually capturing an image and a reference color image by the image capturing means.

  In each of the above embodiments, the luminance of the G image as the inspection color image of the present invention and the luminance of the R image and B image as the reference color image of the present invention are substantially equal to each other. The brightness of the reference color image may be different from each other.

  In each of the above embodiments, a white inspection color image is configured by combining RGB images, but the combination of image colors for forming a white inspection image is not limited to RGB. A white inspection image may be configured using images of other three colors (for example, yellow, cyan, and magenta).

  In each of the above embodiments, the liquid crystal light valve 14G disposed at the position Pg is the inspection target. However, the liquid crystal light valve 14R disposed at the position Pr and the liquid crystal light valve 14B disposed at the position Pb are the inspection target. May be.

  In each of the embodiments, the liquid crystal light valves 14R and 14B having the same configuration as the liquid crystal light valve 14G as the inspection target image display apparatus of the present invention are provided as the reference color image display means of the present invention. The image display means may not have the same configuration as the inspection target image display device. For example, a liquid crystal light valve may be used as the inspection target, and a color image display device such as a color liquid crystal panel may be used as the reference color image display means.

  Further, in each of the above embodiments, an image of each RGB color is displayed by the light of each RGB color extracted from the light source light of the single light source 11. However, a light source is provided for each color, and the light of each color from each light source is provided. You may display the image of each color.

  Moreover, in each said embodiment, although the image for a test | inspection without a pattern was comprised, you may comprise the image for a test | inspection with a pattern, such as a checkered pattern.

  In each of the above embodiments, an inspection image having uniform luminance and color is formed over the entire surface. However, an inspection image having different luminance and color may be formed for each part.

In the second embodiment, the color difference data ΔE ^* ab in the L ^* a ^* b ^* color system is calculated using the equations (1) to (5). However, the color specification for calculating the color difference data is used. The system is not limited to the L ^* a ^* b ^* color system, and color difference data in other color systems may be calculated using a known formula in the color system.

In the second embodiment, the color difference data calculating unit 43 uses the color difference data based on the inspection image imaging data (R, G, B) related to the color of the inspection image acquired by the imaging data acquisition unit 42. In this case, the inspection is performed based on the color difference data. However, the inspection may be performed based on the image data for inspection (R, G, B) without using the color difference data. Since the image data for inspection (R, G, B) includes color information in each part of the image for inspection, the image to be inspected even if the image data for inspection (R, G, B) is used. It is possible to detect an uneven color defect that occurs in an inspection image due to a defect in the display device.
However, if the color difference data is used, the inspection can be performed under a condition closer to the sensitivity of the human eye, so that the inspection can be performed with high accuracy.

In the second embodiment, the counting unit 441 and the defect determination unit 442 detect the defect of the liquid crystal light valve 14G to be inspected based on the number of defect imaging camera pixels, but other methods may be used. It is possible to detect defects in the inspection target image display device.
For example, by applying the uneven defect detection method disclosed in Japanese Patent Application Laid-Open No. 2004-212311 to the color difference data for each camera pixel calculated by the color difference data calculation unit 43, the color in the inspection image is determined. Uneven defects can be detected, and the image display device to be inspected can be inspected with high accuracy. Further, the defect detection of the inspection target image display device may be performed based on the distribution of color difference data for each camera pixel. Further, the defect of the inspection target image display device may be emphasized and detected by applying an appropriate enhancement filter to the color difference data for each camera pixel.

  The present invention can be used for inspection of an image display device.

It is a figure showing the inspection device concerning a 1st embodiment of the present invention. It is a figure which shows the internal structure of the projection apparatus in an inspection apparatus. It is a figure which shows the inspection apparatus which concerns on 2nd Embodiment of this invention. It is a flowchart which shows the flow of the process of the test | inspection by an inspection apparatus. It is a flowchart which shows the flow of acquisition of the reference data used for the test | inspection by an inspection apparatus. It is a figure which shows the point which measures the tristimulus value in each reference | standard image in the case of reference | standard data acquisition. It is a figure which shows a reference | standard R image. It is a figure which shows a reference | standard G image. It is a figure which shows a reference | standard B image. It is a figure which shows a reference | standard W image. It is a table | surface which shows an example of the image pick-up data for an inspection.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Projection apparatus, 2 ... Screen, 3 ... 3CCD camera, 4 ... Control part, 11 ... Light source, 14R, 14G, 14B ... Liquid crystal light valve, 15 ... Projection lens, 41 ... Color image display means, 42 ... Acquisition of imaging data Means 43: Color difference data calculating means 44 ... Inspection means 121, 122, 123, 124 ... Dichroic mirrors 131, 132 ... Reflecting mirrors, 441 ... Counting means, 442 ... Defect judging means.

Claims (12)

An inspection method for an image display device capable of displaying an image,
A color image display step of displaying a test color image of a predetermined test color on the image display device and displaying a reference color image of a reference color different from the test color on a predetermined reference color image display means;
An inspection image construction step for composing one inspection image by combining the inspection color image displayed by the image display device and the reference color image displayed by the reference color image display means,
An inspection method for an image display device, comprising: The inspection method for an image display device according to claim 1,
In the color image display step, the luminance of the inspection color image displayed on the image display device and the luminance of the reference color image displayed on the reference color image display means are substantially equal to each other.
An inspection method for an image display device. The inspection method for an image display device according to claim 2,
Two reference color image display means are provided,
In the color image display step, an inspection color image of any one of R color, G color, and B color is displayed on the image display device, and R color, Displaying the remaining two reference color images of the G and B colors, excluding the one color to be displayed on the image display device, respectively;
An inspection method for an image display device. In the inspection method of the image display apparatus in any one of Claims 1-3,
Two reference color image display means are provided,
In the color image display step, the test color image of G color is displayed on the image display device, and the reference color images of R color and B color are displayed on the two reference color image display means,
An inspection method for an image display device. In the inspection method of the image display device according to any one of claims 1 to 4,
The image display device can generate a colorless inspection image pattern,
In the color image display step, the inspection image pattern is illuminated with light of the inspection color, and an inspection color image of the inspection color based on the inspection image pattern is displayed on the image display device.
An inspection method for an image display device. In the inspection method of the image display device according to claim 5,
The reference color image display means can generate a colorless reference image pattern having the same configuration as the image display device,
In the color image display step, the reference image pattern is illuminated with light of the reference color, and a reference color image of a reference color based on the reference image pattern is displayed on the reference color image display means.
An inspection method for an image display device. In the inspection method of the image display device according to claim 6,
A single light source capable of emitting light source light;
Inspection color light extraction means for extracting light of the inspection color from the light source light;
Reference color light extraction means for extracting light of the reference color from the light source light;
Is provided,
In the color image display step,
The colorless inspection image pattern generated in the image display device is illuminated with the inspection color light extracted by the inspection color light extraction means, and the inspection color image of the inspection color based on the inspection image pattern is displayed on the image display device. Let
And,
The colorless reference image pattern generated in the reference color image display means is illuminated with the reference color light extracted in the reference color light extraction means, and the reference color image of the reference color based on the reference image pattern is the reference color image Display on the display means,
An inspection method for an image display device. In the inspection method of the image display device according to any one of claims 1 to 7,
An imaging data acquisition step of imaging an inspection image configured in the inspection image configuration step by an imaging means having a plurality of imaging pixels and acquiring imaging data related to the color of the inspection image;
When there is no defect in the image display device, the color of the inspection image configured in the inspection image configuration step is set as a reference color, and color difference data relating to the color difference between the reference color and the imaging color of the individual imaging pixels is obtained. A color difference data calculation step for calculating based on the imaging data;
An inspection process for inspecting the image display device based on color difference data for the individual imaging pixels;
An inspection method for an image display device, characterized in that: In the inspection method of the image display device according to claim 8,
In the inspection process,
The color difference data for the individual imaging pixels is compared with a predetermined color difference data threshold value, respectively, and a counting step for counting imaging pixels having color difference data exceeding the color difference data threshold value;
The count value in the counting step is compared with a predetermined count value threshold value, and when the count value exceeds the count value threshold value, it is determined that the image display device is defective, and the count value is equal to the count value threshold value. If not exceeded, a defect determination step for determining that the image display device is not defective,
An inspection method for an image display device, characterized in that: An image display apparatus inspection apparatus capable of displaying an image,
A color image display unit that displays a test color image of a predetermined test color on the image display device and displays a reference color image of a reference color different from the test color on a predetermined reference color image display unit;
An inspection image composing unit configured to compose one inspection image by combining the inspection color image displayed by the image display device and the reference color image displayed by the reference color image display unit;
An inspection apparatus for an image display device, comprising: The inspection apparatus for an image display device according to claim 10,
Imaging data acquisition means for imaging an inspection image configured in the inspection image configuration means by an imaging means having a plurality of imaging pixels and acquiring imaging data related to the color of the inspection image;
Color difference data calculating means for calculating color difference data related to a color difference between a predetermined reference color and the image pickup color of each individual image pickup pixel based on the image pickup data;
Inspection means for inspecting the image display device based on color difference data about the individual imaging pixels;
An inspection apparatus for an image display device, comprising: The inspection apparatus for an image display device according to claim 10 or 11,
The image display device can generate a colorless inspection image pattern, and can be attached to and detached from the illumination position of the inspection color light,
The color image display means generates an inspection image pattern on the image display device arranged at the illumination position of the inspection color light, and displays an inspection color image of the inspection color based on the inspection image pattern.
An inspection apparatus for an image display device.

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